Consumers more and more often replace conventional incandescent lamps with single-ended low-pressure mercury vapor discharge lamps commonly known as compact fluorescent lamps. The reason for this is that these lamps have small size comparable to an incandescent lamp so as to fit within the same sockets and fixtures, and at the same time have luminous efficiencies many times greater that of the incandescent lamps. To achieve even a slight further increase in efficiency, lampmakers are making great efforts. It is known that the efficiency can be increased by using appropriately chosen phosphors with as uniform phosphor coating as possible. Additionally, further efficiencies can be gained by using an appropriately chosen frequency for the electronic circuitry that operates the lamp; an example of such circuitry as can be found in U.S. Pat. No. 5,341,068 issued to Nerone on Aug. 23, 1994, and herein incorporated by reference.
Accordingly, it would be advantageous to further improve the efficiency of single-ended low-pressure mercury vapor discharge lamps by minimizing the loss of light from the discharge lamp by providing those end portions of the tube portions of the discharge lamp, which end portions are adjacent to the top housing part of the discharge lamp, with a light-reflecting layer.